Charge-Regulation Module Calibration in Vacuum
Solution Overview
Problem
Charged particle beam tools, such as SEMs, face challenges in accurately calibrating charge-regulation modules within vacuum environments due to the need to break the vacuum for traditional calibration methods, which are time-consuming and inefficient, leading to deteriorated charge conditions on wafer surfaces.
Innovation Solution
A system and method for calibrating charge-regulation modules within a vacuum environment using a Laser beam spot that can be moved to a pre-determined position by motors and a transmission system, allowing for precise control and calibration without breaking the vacuum, utilizing a detector and controller to adjust the beam spot's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration method is used to calibrate charge-regulation module, then calibration can be performed, but vacuum environment must be broken which makes the process time-consuming (2 days or longer)
Solution Approach 1:
A fiducial marker is introduced as an intermediary reference object on the wafer surface. The marker serves as a common reference point that both the charged particle beam system and laser calibration system can detect and align to, enabling accurate calibration without breaking vacuum. The marker acts as a mediator that translates between the coordinate systems of the two systems.
Solution Approach 2:
The invention creates an optical copy or projection of the fiducial marker position using the laser beam. By projecting the laser beam to coincide with the charged particle beam position at the fiducial marker, the system creates a visual reference that allows calibration without direct physical access to the beam interaction point, thus maintaining vacuum while achieving alignment.
2Adaptability or versatility
If charge-regulation module is mounted to charged particle beam tool, then charge regulation function is added, but beam spot position may deviate from charged particle beam position due to installation or operation
Solution Approach 1:
The system uses feedback from detecting the fiducial marker position to adjust and align the laser beam spot position. By continuously monitoring the marker position and adjusting the laser accordingly, the system compensates for any installation or operational deviations, ensuring the laser beam spot coincides with the charged particle beam position at the fiducial marker.
3Reliability
If charged particle tool operates in vacuum chamber, then proper beam operation is maintained, but calibration procedure requires breaking vacuum to atmosphere which is time-consuming
Solution Approach 1:
The calibration system is designed to perform calibration functions entirely within the vacuum environment. The fiducial marker detection and laser alignment processes are self-contained operations that do not require external atmospheric conditions, allowing the vacuum chamber to remain sealed and maintaining continuous vacuum conditions throughout the calibration process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid and precise calibration of charge-regulation modules within the vacuum environment, reducing calibration time from days to minutes, thereby maintaining optimal charge conditions on wafer surfaces and improving defect identification in semiconductor manufacturing.
Implementation Method 1
One charge regulation module is to use Laser illuminating onto the wafer surface, and charged can be regulated due to photoconductivity and/or photoelectric effect
Implementation Method 2
One charge regulation module is to use Laser illuminating onto the wafer surface, and charged can be regulated due to photoconductivity and/or photoelectric effect
Implementation Method 3
The detector receives a reflected beam from the beam spot on the sample surface
Data Source
AI summary
This invention provides a system and a method for calibrating charge-regulation module in vacuum environment. Means for mounting the charge-regulation module provides motions to the charge-regulation module such that a beam spot, illuminated by the charge-regulation module, on a sample surface can be moved to a pre-determined position which is irradiated by a charged particle beam.